Process for the preparation of ring compounds

ABSTRACT

In a process for the preparation of ring compounds via a combinatorial synthesis, the reaction procedure is based on a Suzuki coupling; subsequent halo-demetallation and finally a further Suzuki coupling. The Suzuki couplings are each carried out with a boronic acid or a boronic acid ester. The reaction procedure uses provides novel ring compounds and uses novel synthesis units used for this purpose. The novel ring compounds are suitable for use as constituents in liquid-crystalline mixtures.

This application is a continuation of U.S. Ser. No. 12/907,612, filed Oct. 19, 2010, now U.S. Pat. No. 8,124,817, which is a divisional of U.S. Ser. No. 12/470,605, filed May 22, 2009, now U.S. Pat. No. 7,842,845, which is a divisional of U.S. Ser. No. 12/188,288, filed Aug. 8, 2008, now U.S. Pat. No. 7,786,332, which is a divisional of U.S. Ser. No. 11/437,608, filed May 22, 2006, now U.S. Patent No. 7,411,100, which is a divisional of U.S. Ser. No. 10/388,607, filed Mar. 17, 2003, now U.S. Pat. No. 7,183,447.

The present invention relates to a process for the preparation of ring compounds via a combinatorial synthesis based on a Suzuki coupling, subsequent halo-demetallation and finally a Suzuki coupling. The Suzuki couplings are each carried out with a boronic acid or a boronic acid ester. The present invention likewise relates to the corresponding ring compounds and to the novel synthesis units used for this purpose. The ring compounds according to the invention are preferably used as constituents in liquid-crystalline mixtures.

The prior art discloses the palladium-catalysed cross-coupling reaction of aromatic boron compounds, such as boronic acids and derivatives thereof, and aromatic halogen compounds (EP 0 470 795 A1), which has for some years also increasingly been used in the area of organic synthesis. The process described in EP 0 470 795 A1 is based on a homogeneously catalysed process using palladium(0) complexes, in particular tetrakis-(triphenylphosphine)palladium(0). It is disadvantageous in this process that the complexes are oxidation-sensitive, causing them to lose activity. Owing to the varying activity, the process is difficult to reproduce and the yields are in some cases very low. In addition, the complexes are very expensive.

DE 44 26 671 A1 discloses a process for the preparation of polycyclic aromatic compounds by cross-coupling aromatic boron compounds with aromatic halogen compounds or perfluoroalkyl sulfonates with palladium catalysis in the presence of at least one water-soluble complex ligand. This process is carried out with a 2-phase system comprising an organic phase and an aqueous phase, with the palladium catalyst being dissolved in the organic phase. It is disadvantageous in this process that very good mixing of the two phases is a prerequisite for the reaction. In addition, this process is also very expensive owing to the catalysts employed.

Starting from this prior art, an object of the present invention is to provide a process or to develop a combinatorial synthesis strategy with which products can be obtained in high yield and high conversion with a small number of reaction steps.

Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.

These objects are achieved in accordance with the invention by a process comprising subjecting a compound of formulae V to VIII

-   -   wherein     -   Z is I, Cl, Br or triflate,     -   M is Si, Ge or Sn, and     -   R³, R⁴     -   and R⁵, independently of one another, are identical or different         and are each H, C₁-C₁₂-alkyl or C₁-C₁₂-alkoxy,     -   via combinatorial synthesis, to the following reaction steps         which are carried out in a matrix-like arrangement of reaction         vessels:     -   A) Suzuki coupling with a boronic acid or a boronic acid ester         of formula X

-   -   -   wherein         -   R⁶ and R⁷, independently of one another, are identical or             different and are each H, C₁-C₁₂-alkyl, C₂-C₁₂-alkenyl or             aryl, and where R⁶ and R⁷ can also be bridged in a cyclic             manner;

    -   B) subsequent halo-demetallation; and

    -   C) Suzuki coupling with a boronic acid or a boronic acid ester         of formula XI

-   -   wherein one or two CH groups in the aromatic ring systems of         formulae V to VIII, X and XI may each also be replaced by N.

The invention further relates to liquid-crystalline ring compounds of formula XII

-   -   wherein     -   one or two CH groups in the aromatic ring systems of formula         XIII may each be replaced by N;     -   Y is a group of formulae XIV to XVI

-   -   in which one or two CH groups in the aromatic ring systems may         each be replaced by N;     -   m and n, independently of one another, are identical or         different and are each 0 or 1, and the sum m+n is 1 or 2;     -   X is a single bond, —CH₂—CH₂—, —OH═CH—, —C≡C— or

-   -   L, independently of one another, are identical or different and         are each R; F, Cl, Br, I, BH, OR, SH, SR, CN, NO₂, NO, CHO,         COOH, COOR, —CONH₂, CONHR, CONR₂, CF₃, NH₂, NHR or NR₂;     -   R is an alkyl, alkenyl or acyl group having up to 12 carbon         atoms or an aryl group having 6 carbon atoms which is optionally         substituted by an alkyl group having from 1 to 12 carbon atoms;         and     -   a, b, c, d,     -   e and f, independently of one another, are identical or         different and are each 0, 1 or 2, and the sum a+b+c+d+e+f is 1         to 8, preferably 3 to 8;     -   R¹ and R², independently of one another, are identical or         different and are each H, F, Cl, CN, NCS, a straight-chain or         branched, optionally chiral alkyl radical or alkoxy radical         having from 1 to 12 carbon atoms or an alkenyl radical or         alkynyl radical having from 2 to 8 carbon atoms, in each of         which, in addition, one CH₂ group may be replaced by —O—, —CO—,         —O—CO—, —COO— or —CH═CH— in such a way that heteroatoms are not         linked directly to one another and/or one or more H may be         replaced by halogen, preferably F; and     -   in the case where m is 0 or n is 0, one CH₂ group in R¹ or R²         may be replaced by one of the following groups:     -   a) trans-1,4-cyclohexylene, in which, in addition, one or more         non-adjacent CH₂ groups may each be replaced by —O— or —S—,     -   b) a radical from the group consisting of         1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl,         naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and         1,2,3,4-tetrahydronaphthalene-2,6-diyl, or     -   c) 1,4-cyclohexenylene,         and in which the radicals a), b) and c) may also be substituted         by CN and/or halogen.

In accordance with a further aspect of the invention there are provide boronic acids or boronic acid ester compounds as synthesis units, including:

boronic acid or boronic acid ester compounds of formula XIX

-   -   wherein     -   one or two CH groups in the aromatic ring system may each be         replaced by N;     -   r is 1 or 2;     -   R is H, F, Cl, CN, NCS, a straight-chain or branched, optionally         chiral, alkyl radical or alkoxy radical having from 1 to 12         carbon atoms or an alkenyl radical or alkynyl radical having         from 2 to 8 carbon atoms, in each of which, in addition, one C₂         group may be replaced by —O—, —CO—, —O—CO— or —COO— in such a         way that heteroatoms are not linked directly to one another         and/or one or more H may be replaced by halogen;     -   the L groups, independently of one another, are identical or         different and are each R′, F, Cl, Br, I, OH, OR′, SH, SR′, CN,         NO₂, NO, CHO, COOH, COOR′, CONH₂, CONHR′, CONR′₂, CF₃, NH₂, NHR′         or NR′₂;     -   R′ is an alkyl, alkenyl or acyl group having from up to 12         carbon atoms or an aryl group having 6 carbon atoms, which is         optionally substituted by an alkyl group having from 1 to 12         carbon atoms;     -   a, is 0, 1 or 2;     -   R⁶ and R⁷, independently of one another, are identical or         different and are each H, C₁-C₁₂-alkyl, C₂-C₁₂-alkenyl or aryl,         and where R⁶ and R⁷ can also be bridged in a cyclic manner; and         boronic acid or boronic acid ester compound of formula XXI

-   -   wherein     -   one or two CH groups in the aromatic ring system may each be         replaced by N;     -   r is 1 or 2;     -   R³, R⁴     -   and R⁵, independently of one another, are identical or different         and are each H, C₁-C₁₂-alkyl or C₂-C₁₂-alkoxy;     -   R⁶ and R⁷, independently of one another, are identical or         different and are each H, C₁-C₁₂-alkyl, C₂-C₁₂-alkenyl or aryl,         and where R⁶ and R⁷ can also be bridged in a cyclic manner;     -   M is Si, Ge or Sn;     -   the L groups, independently of one another, are identical or         different and are each R′, F, Cl, Br, I, OH, OR′, SH, SR′, CN,         NO₂, NO, CHO, COOH, COOR′, CONH₂, CONHR′, CONR′₂, CF₃, NH₂, NHR′         or NR′₂;     -   R′ is an alkyl, alkenyl or acyl group having from up to 12         carbon atoms or an aryl group having 6 carbon atoms, which is         optionally substituted by an alkyl group having from 1 to 12         carbon atoms; and     -   a, is 0, 1 or 2.

In accordance with the invention, a process is provided for the preparation of ring compounds of the general formulae I to IV

In these formulae, m and n, independently of one another, are identical or different and can adopt the values 0 or 1, where the sum (m+n) is 1 or 2.

Particularly preferably, m=n=1, i.e. the sum (m+n)=2.

X is a single bond, —CH₂—CH₂, —CH═CH—, —C≡C— or

X is preferably a single bond.

The L groups, independently of one another, are identical or different and are each R, F, F, Cl, Br, I, OH, OR, SH, SR, CN, NO₂, NO, CHO, COOH, COOR, CONH₂, CONHR, CONR₂, CF₃, NH₂, NHR or NR₂, where R is an alkyl, alkenyl or aryl group having from 1 to 12 carbon atoms or an aryl group having 6 carbon atoms, which may, if desired, in turn be substituted by an alkyl group having from 1 to 12 carbon atoms. The L groups are preferably, independently of one another, identical or different, and are each F, Cl, CF₃ or CH₃, where F is particularly preferred.

The indices a, b, c, d, e and f may, independently of one another, be identical or different and adopt the values 0, 1 or 2, where the sum a+b+c+d+e+f adopts values between 1 and B, preferably between 3 and 8 and particularly preferably between 4 and 8. One or two OH groups in the aromatic ring systems of the formulae I to IV may each be replaced by N.

R¹ and R², independently of one another, are identical or different and are H, F, Cl, CN or NCS. It is likewise possible for R¹ and/or R² to be a straight-chain or branched, optionally chiral alkyl radical or alkoxy radical having from 1 to 12 carbon atoms or an alkenyl radical or alkynyl radical having from 2 to 8 carbon atoms, where one CH₂ group in each of these organic radicals may also be replaced by —O—, —CO—, —O—CO— or —COO— in such a way that heteroatoms are not linked directly to one another and/or one or more H may be replaced by halogen, preferably F. R¹ and/or R² are preferably a straight-chain alkyl radical having from 1 to 7 carbon atoms. In a further preferred embodiment, R² is a chiral alkyl radical having from 1 to 12 carbon atoms.

In the case where m=0 or n=0, one CH₂ group in R¹ or R² is preferably replaced by one of the following groups

-   a) trans-1,4-cyclohexylene, in which, in addition, one or more     non-adjacent CH₂ groups may each be replaced by —O— or —S—, -   b) a radical from the group consisting of 1,4-bicyclo[22.2]octylene,     piperidine-1,4-diyl, naphthalene-2,6-diyl,     decahydronaphthalene-2,6-diyl and     1,2,3,4-tetrahydronaphthalene-2,6-diyl, or -   c) 1,4-cyclohexenylene.

The radicals a), b) and c) may also be substituted by CN and/or halogen.

If R¹ and/or R² in the formulae above and below are an alkyl radical, this may be straight-chain or branched. It is particularly preferably straight-chain, has 1, 2, 3, 4, 5, 6 or 7 carbon atoms and is accordingly methyl, ethyl, propyl, butyl, pentyl, hexyl or heptyl, furthermore octyl, nonyl, decyl, undecyl or dodecyl.

If R¹ and/or R² are an alkyl radical in which one CH₂ group has been replaced by —O—, this may be straight-chain or branched. It is preferably straight-chain and has from 1 to 10 carbon atoms. The first CH₂ group in this alkyl radical is particularly preferably replaced by —O—, so that the radical R¹ attains the meaning alkoxy and is methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy or nonyloxy.

It is furthermore also possible for a CH₂ group elsewhere to be replaced by —O—, so that the radical R¹ and/or R² is preferably straight-chain 2-oxapropyl (=methoxymethyl), 2-(=ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxodecyl.

If R¹ and/or R² are an alkyl radical in which one CH₂ group has been replaced by —O— and one has been replaced by —CO—, these are adjacent. These thus contain an acyloxy group —CO—O— or an oxycarbonyl group —O—CO—. These are particularly preferably straight-chain and have from 2 to 6 carbon atoms.

Accordingly, they are in particular acetoxy, propionyloxy, butyryloxy, pentanoyloxy, hexanoyloxy, acetoxymethyl, propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetoxyethyl, 2-propionyloxyethyl, 2-butyryloxyethyl, 3-acetoxypropyl, 3-propionyloxypropyl, 4-acetoxybutyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, propoxy-carbonylmethyl, butoxycarbonylmethyl, 2-(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl, 2-(propoxycarbonyl)ethyl, 3-(methoxycarbonyl)-propyl, 3-(ethoxycarbonyl)propyl and 4-(methoxycarbonyl)butyl.

If R¹ and/or R² are an alkyl or alkenyl radical which is monosubstituted by CN or CF₃, this radical is preferably straight-chain and the substitution by CN or CF₃ is in the ω-position.

If R¹ and/or R² are an alkyl radical which is at least monosubstituted by halogen, this radical is preferably straight-chain. Halogen is preferably F or Cl. In the case of polysubstitution, halogen is preferably F. The resultant radicals also include perfluorinated radicals. In the case of monosubstitution, the fluorine or chlorine substituent can be in any desired position, but preferably in the ω-position.

Compounds of the formula I having a branched wing group R¹ and/or R² may occasionally be of importance owing to better solubility in the conventional liquid-crystalline base materials, but in particular as chiral dopants if they are optically active. Smectic compounds of this type are suitable as components of ferroelectric materials.

Branched groups of this type generally contain not more than one chain branch. Preferred branched radicals R¹ and/or R² are isopropyl, 2-butyl (=1-methylpropyl), isobutyl (=2-methylpropyl), 2-methylbutyl, isopentyl (=3-methylbutyl), 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propyl-pentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentyloxy, 3-methylpentyloxy, 2-ethylhexyloxy, 1-methylhexyloxy and 1-methylheptyloxy.

The groups m, n, X, L, a, b, c, d, e, f, R¹ and R² below are as defined above unless expressly stated otherwise. Correspondingly, one or two CH groups in the ring systems mentioned below may also each be replaced by N analogously to the ring compounds of the general formulae I to IV.

The ring compounds of the general formulae I to IV are prepared starting from the compounds of the formulae V to VIII:

-   Z here is selected from the group consisting of I, Cl, Br and OTf     (triflate), where Z is preferably I, and M is selected from the     group consisting of Si, Ge and Sn, where Si is preferred. -   R³, R⁴ and R⁵, independently of one another, are identical or     different and are H, C₁-C₁₂-alkyl or C₁-C₁₂-alkoxy.

Furthermore, at least one of the radicals R³, R⁴ and R⁵ in the general formulae V to VIII can be a fluorine-containing alkyl radical of the general formula IX —(CH₂)_(p)—(CF₂)_(q)—CF₃  IX where p can adopt values in the range from 2 to 4, q can adopt values≧2, and the sum (p+q) can adopt values in the range from 2 to 11, q is preferably >p.

-   R^(, 3), R⁴, R⁵, M and Z below are as defined above unless expressly     stated otherwise.

The ring compounds are prepared via combinatorial synthesis, in which the following reaction steps are carried out in a matrix-like arrangement of reaction vessels:

-   A) Suzuki coupling with a boronic acid or a boronic acid ester,     preferably a boronic acid ester, of the general formula X

-   -   where R⁶ and R⁷, independently of one another, are identical or         different and are H, C₁-C₁₂-alkyl, C₂-C₁₂-alkenyl, preferably         C₃-C₁₂-alkenyl, or C₆₋₁₀-aryl (preferably C-aryl). R⁶ and R⁷ may         also be bridged in a cyclic manner.     -   R⁶ and R⁷ below are as defined above unless expressly stated         otherwise.

-   B) subsequent halo-demetallation, preferably iodo-desilylation, and

-   C) Suzuki coupling with a boronic acid or a boronic acid ester,     preferably a boronic acid ester, of the general formula XI

In a step preceding step A), the compound of the formula V, in which X is a single bond, is preferably prepared from a boronic acid or a boronic acid ester of the formula XII

by Suzuki coupling with an at least partially fluorinated p-bromoiodo-benzene, which is carried out as a combinatorial synthesis in a matrix-like arrangement of reaction vessels, with a subsequent iodination step for substitution of the bromine, for example by means of butyllithium and an iodinating agent.

A particular advantage of the process according to the invention is that this is carried out as a combinatorial synthesis. For the development of combinatorial synthesis, it is necessary to develop a synthesis concept with reactions matched to one another, with the aim being to optimise the reactions with respect to conversion and yield. The process is carried out as a divergent synthesis, which has the advantage over a linear synthesis that only three reaction steps are needed. Linear synthesis, by contrast, would require five reaction steps. A further advantage is the smaller purification effort compared with the performance of a linear synthetic process.

The intermediates and/or end products are preferably purified by recrystallisation, and the crystals are isolated via-cartridges for solid-phase extraction, with the purification being carried out in parallel for all reaction vessels.

Regarding the Suzuki couplings, the base needed for this purpose is preferably selected from the group consisting of the hydroxides, carbonates and fluorides, with barium hydroxide and caesium fluoride being particularly preferred.

The catalyst employed is preferably a palladium-containing compound, particularly preferably palladium acetate.

The reaction is preferably carried out in a polar solvent, such as, for example, an alcohol or ether. Particular preference is given here to the use of isopropanol.

In a further particularly preferred variant of the Suzuki coupling, the base employed is caesium fluoride, the catalyst employed is palladium acetate, and the solvent employed is dioxane.

The preferred Suzuki coupling variants described here have the advantage that virtually quantitative conversion is achieved and the product is free from palladium. At the same time, no by-products which cannot be separated off are formed, meaning that the purity of the crude products is adequate for the subsequent reactions. Further advantages of this catalyst are its simple handling, its stability in air and it low price.

The Suzuki couplings are preferably carried out at a temperature between 10 and 120° C. and a reaction duration between 0.1 and 30 hours. Particular preference is given to temperatures between 50 and 100° C. and a reaction duration between 18 and 24 hours.

The iodo-desilylation, as the preferred variant of the halo-demetallation, is preferably carried out with addition of iodine chloride in methyl cyanide. Temperatures between 10 and 75° C. and a reaction duration between 0.1 and 20 hours are preferably observed here. Particular preference is given to temperatures between 20 and 30° C. and a reaction duration between 0.5 and 2 hours.

An important step in the synthesis is suppression of side-chain chlorinations during the halo-demetallation. This side-chain chlorination of the radicals R¹ and R² can be prevented virtually completely if an iodo-desilylation is carried out in acetonitrile. A further reason for the preference for iodo-desilylation in combination with the Suzuki coupling is its compatibility with respect to fluorine substituents in the o-position.

The process according to the invention for the preparation of ring compounds of the general formulae I to IV is shown in detailed diagrammatic form below for the preferred ring compounds of the general formula XVIII.

The preparation of the biphenyl, the starting substance of the process according to the invention, is shown in scheme 1. Scheme 2 shows the synthesis of the terphenyl starting from the biphenyl from scheme 1 and a boronic acid (step A of the process according to the invention). Scheme 3 describes the iodo-desilylation of the terphenyl from scheme 2 (step B of the process according to the invention), and scheme 4 describes the synthesis of the quaterphenyl (step C of the process according to the invention).

Ring compounds of the general formula XII

where m and n, independently of one another, are identical or differed and adopt the value 0 or 1, where the sum (m+n) is 1 or 2, preferably m=n=1, i.e. the sum (m+n)=2, are likewise prepared in accordance with the invention.

Y here is a group of the general formulae XIV to XVII

where X=single bond, —CH═OH—, —C≡C— or

L, independently of one another, are identical or different and are R, F, Cl, Br, I, OH, OR, SH, SR, CN, NO₂, NO, CHO, COOH, COOR, CONH₂, CONHR, CONR₂, CF₃, NH₂, NHR or NR₂, where R is an alkyl, alkenyl or acyl group having from 1 to 12 carbon atoms or an aryl group having 6 carbon atoms, which may, if desired, in turn be substituted by an alkyl group having from 1 to 12 carbon atoms. L are preferably, independently of one another, identical or different, and are F, Cl, CF₃ or CH₃, where F is particularly preferred.

The indices a, b, c, d, e and f may, independently of one another, be identical or different and adopt the values 0, 1 or 2, where the sum (a+b+c+d+e+f adopts values between 1 and 8, preferably between 3 and 8 and particularly preferably between 4 and 8. One or two CH groups in the aromatic ring systems of the formulae XIII to XVII may each be replaced by N.

R¹ and R², independently of one another, are identical or different and are H, F, Cl, CN or NCS. It is likewise possible for R¹ and/or R² to be a straight-chain or branched, optionally chiral alkyl radical or alkoxy radical having from 1 to 12 carbon atoms or an alkenyl radical or alkynyl radical having from 2 to 8 carbon atoms, where one CH₂ group in each of these organic radicals may also be replaced by —O—, —CO—, —O—CO—, —COO— or —CH═CH— in such a way that heteroatoms are not linked directly to one another and/or one or more H may each be replaced by halogen, preferably F.

In the case where m=0 or n=0, one CH₂ group in R¹ or R² must be replaced by one of the following groups:

-   a) trans-1,4-cyclohexylene, in which, in addition, one or more     non-adjacent CH₂ groups may each be replaced by —O— or —S—, -   b) a radical from the group consisting of     1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl,     naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and     1,2,3,4-tetrahydronaphthalene-2,6-diyl, or -   c) 1,4-cyclohexenylene.

The radicals a), b) and c) here may also be substituted by CN and/or halogen.

Preference is given to ring compounds of the general formula XVIII

where particularly preferably m=n=1, and the radical R¹ and R², independently of one another, are identical or different and are selected from the group C₁-C₇-alkyl.

Particular preference is given here to ring compounds of the following formulae XVIIIa to XVIIIg:

where R¹ and R² are as defined above in respect of formula XVIII, L¹, L² and L³ can adopt the meanings of L^(d), and L⁴, L⁵ and L⁶ can adopt the meanings of L^(a) Particular preference is given here to the ring compounds of the formulae XVIIIf and XVIIIg.

Boronic acids or boronic acid esters of the general formula XIX

are also prepared in accordance with the invention as synthesis units.

The boronic acids or boronic acid esters preferably have a structure in accordance with the general formula XX

In the structures XIX and XX, r can be =m or n and can thus adopt the values 1 or 2, preferably 1. If r=M, then R═R¹, and if r=n, then R═R²

R can be as defined for R¹ and R² and is thus H, F, Cl, CN or NOS.

It is likewise possible for R to be a straight-chain or branched, optionally chiral alkyl radical or alkoxy radical having from 1 to 12 carbon atoms or an alkenyl radical or alkynyl radical having from 2 to 8 carbon atoms, where one CH₂ group in this organic radical may also be replaced by —O— or —COO— in such a way that heteroatoms are not linked directly to one another and/or one or more H may each be replaced by F. In addition, in the case where r=0, one CH₂ group in R may also be replaced by one of the following groups:

-   a) trans-1,4-cyclohexylene, in which, in addition, one or more     non-adjacent CH₂ groups may each be replaced by —O— or —S—, -   b) a radical from the group consisting of     1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl,     naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1,     2,3,4-tetrahydronaphthalene-2,6-diyl, or -   c) 1,4-cyclohexenylene.

R⁶, R⁷, L and a here are as defined above.

R⁸ and R⁹, independently of one another, are identical or different and are C₁-C₁₂-alkyl or C₆₋₁₀-aryl (preferably C₆-aryl).

Furthermore, boronic acids or boronic acid esters of the general formula XXI

are prepared in accordance with the invention.

The boron acids or boronic acids or boronic acid esters preferably have the general formula XXII

M, r, R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, L and a here are as defined above.

One or two CH groups in the aromatic ring systems of the general formulae XIX, XX, XXI and XXII may likewise each be replaced by N.

The entire disclosure of all applications, patents and publications, cited above and below, and of corresponding German Application No. 10211597.4, filed Mar. 15, 2002, is hereby incorporated by reference.

The invention is described in greater detail below with reference to working examples, in which illustrative compounds according to the invention are mentioned which have been prepared by combinatorial synthesis, but without in any way being restricted thereby.

Above and below, percentages are percent by weight.

At the same time, these compounds have been characterised with reference to their phase transitions.

C denotes crystalline state, N=nematic phase, Sm=smectic phase and I=isotropic phase. The data between these symbols are the transition temperatures. All temperatures are give in degrees Celsius.

EXAMPLE 1 Preparation of the Boronic Acid (4)

4-Bromo 2,6-difluorobenzaldehyde (1)

55 ml (0.11 mmol) of 2 M lithium diisopropylamide are added with stirring at −70° C. to a solution of 19.3 g (0.1 mmol) of 1-bromo-3,5-difluorobenzene in 120 ml of dried tetrahydrofuran. After 30 minutes, N-formylpiperidine is added dropwise at this temperature. The mixture is allowed to warm to 0° C. At about 0° C., the reaction mixture is poured into cold water, acidified using 10% HCl and extracted twice with methyl tert-butyl ether. The combined organic phases are washed with water, dried over NaSO₄ and filtered, and the solvent is removed under reduced pressure. The residue is filtered through SiO₂ (heptane/dichloromethane 1:1), (yield: 17.6 g, 78%).

5-Bromo-1,3-difluoro-2-[(R)-3-methylpent-1-enyl]benzene (2)

Phosphonium Salt Synthesis

10 g (66 mmol) of S-(+)-1-bromo-2-methylbutane and 17.4 g (66 mmol) of triphenylphosphine are dissolved in 50 ml of toluene and stirred at 110° C. for 48 hours. The mixture is allowed to warm to room temperature, and the solid is then filtered off and rinsed with toluene (6.9 g, 25%).

The phosphonium salt (6.9 g, 16.7 mmol) is suspended i±25 ml of dried tetrahydrofuran and cooled to from 0 to 5° C. At this temperature, 8.3 ml (16.7 mmol) of 2 M lithium diisopropylamide are added dropwise. After 15 minutes, a solution of 38 g (16.7 mmol) of in 25 ml of dried tetrahydrofuran is added dropwise. The mixture is allowed to warm to room temperature and is stirred at this temperature for 1 hour. Water is subsequently added, and the mixture is acidified using 10% HCl and extracted twice with methyl tert-butyl ether. The combined organic phases are washed with water, dried over Na₂SO₄ and filtered, and the solvent is removed under reduced pressure. The residue is filtered through SiO₂ (heptane), (yield: 1.8 g, 22%).

5-Bromo-1,3-difluoro-2-[(R)-3-methylpentyl]benzene (3)

0.4 g of 5% Pt/C (dry) is added to a solution of 1.8 g (5.9 mmol) of 2 in 50 ml of heptane, and the mixture is hydrogenated at atmospheric pressure for 20 hours. The solvent is removed under reduced pressure, and the entire amount is converted into 4.

3,5-Difluoro-4-[((R)-3-methylpentyl)phenyl]phenylboronic acid (4)

3.3 ml (5.5 mmol) of 1.6 M BuLi are added dropwise at −78° C. to a solution of 1.4 g (5 mmol) of 3 in 5 ml of dry diethyl ether. After 30 minutes, 0.6 ml (5.5 mmol) of trimethyl borate is added dropwise. The mixture is allowed to warm to room temperature overnight. 5.2 ml of water, 5.2 ml of methyl tert-butyl ether and 3 ml of cone. HCl are subsequently added. The organic phase is washed with water (2×3 ml) and sat, NaCl (1×3 ml) and dried using magnesium sulfate, and the solvent is removed under reduced pressure. The residue is filtered through SiO₂ (heptane/dichloromethane 1:1), (yield: 0.8 g, 70%).

EXAMPLE 2 Preparation of the biphenyl (8)

1,2-Difluoro-3-triethylsilylbenzene (5)

625 ml (1 mol) of 1.6 M BuLi are added dropwise at −78° C. to a solution of 114 g (1 ml) of 1,2-difluorobenzene in 11 of dry tetrahydrofuran. After 1 hour, 140 ml (120 g, 1.1 mol) of trimethylsilyl chloride are slowly added dropwise at −78° C. The mixture is allowed to warm to room temperature overnight, and then 200 ml of methyl ter-butyl ether and 200 ml of water are added. The organic phase is washed with water (2×100 ml) and sat. NaCl (1×100 ml) and dried using magnesium sulfate, and the solvent is removed under reduced pressure. 170 g (91%) of 5 distil over from the residue at from 100 to 102° C./70 mbar.

2-(2,3-Difluoro-4-trimethylsilylphenyl)-5,5-dimethyl-1,3,2-dioxaborinane (6)

625 ml (1 mol) of 1.6 M BuLi are added dropwise at −78° C. to a solution of 169 g (910 mmol) of 1,2-difluoro-3-trimethylsilylbenzene (δ) in 1.4 l of dry tetrahydrofuran. After 15 minutes, 276 ml (1.2 mol) of triisopropyl borate are added dropwise. The mixture is allowed to warm to room temperature overnight. 200 ml of water, 200 ml of methyl tert-butyl ether and 100 ml of conc. HCl are subsequently added. The organic phase is washed with water (2×100 ml) and sat. NaCl (1×100 ml) and dried using magnesium sulfate, and the solvent is removed under reduced pressure. The oily residue is dissolved in 270 ml of THF, and 94 g (910 mmol) of neopentyl glycol and 455 g of magnesium sulfate are added. After the mixture has been stirred for 1 hour, the solvent is removed under reduced pressure, and petroleum ether (273 ml) is added to the oily residue. Precipitated neopentyl glycol is removed by filtration. 251 g (87%) of 6 crystallise from the filtrate at −25° C.

(4′-Bromo-2,3,2′-trifluorobiphenyl-4-yl)trimethylsilane (7)

A solution of 16.6 g (120 mmol) of K₂CO₃ in 50 ml of water is added to a solution of 15 g (50 mmol) of 4-bromo-2-fluoro-1-iodobenzene, 14.9 g (50 mmol) of 6 and 2.31 g (2 mmol) of [Pd(PPh₃)₄] in 100 ml of dioxane, and the mixture is refluxed overnight. The organic phase is washed with water and sat. NaCl, dried over MgSO₄ and filtered through SiO₂. The solvent is removed under-reduced pressure, petroleum ether is added to the oily residue, and the product is recrystallised at −25° C. (yield: 88%, m.p. 78.0° C.).

Trimethyl(2,3,2′-trifluoro-4′-iodobiphenyl-4-yl)silane (3)

30 ml (48 mmol) of 1.6 M BuLi are added dropwise at −78° C. to a solution of 15.8 g (44 mmol) of 7 in 132 ml of dry THF. After 15 minutes, 16 g (57.2 mmol) of 1,2-diiodoethane are added as solid, and the mixture is allowed to warm to room temperature over the course of 1 hour. Water and methyl tert-butyl ether are subsequently added. The organic phase is washed with water, sat. Na₂S₂O₅ and sat. NaCl, dried over MgSO₄ and filtered through SiO₂. The solvent is removed under reduced pressure, petroleum ether is added to the oily residue, and the product is recrystallised at −25° C. (yield: 84%, m.p. 76.0° C.).

EXAMPLE 3 Preparation of the terphenyl (10)

Trimethyl-(2,3,2′-trifluoro-4″-propyl-[1,1′;4′,1″]-terphenyl-4-yl)silane (9)

A solution of (2 mmol) of 8, (2.2 mmol) of 4-propylphenylboronic acid, 250 mg (2.40 mmol) of neopentyl glycol, 1:53 g (4.84 mmol) of Ba(OH)₂. 8H₂O, 1.35 ml (0.103 mmol, 5 mol %) of a 76 mM acetone solution of Pd(OAc)₂ in 20 ml of 95% i-PrOH is stirred at 80° for 12 hours. The solvent is subsequently removed under reduced pressure. 5 ml of 2 M HCl are added to the residue, and the mixture is extracted with dichloromethane (3×5 ml). The combined organic phases are dried over MgSO₄ and filtered through SiO₂. The solvent is removed under reduced pressure, and the residue is converted into 10 (yield: 89%).

2,3,2′-Trifluoro-4-iodo-4″-propyl-[1,1′;4′,1″]-terphenyl (10)

The total amount of the terphenyl 9 is dissolved in 4 ml of absolute acetonitrile and reacted with 1.2 ml (6 mmol) of a 5 M solution of ICl in acetonitrile, and the mixture is stirred at room temperature for 1 hour. The residue is crystallised at −20° C. for 2 hours. The supernatant solution is subsequently sucked off, and the product which remains is washed with 2 M Na₂S₂O₅ (10 ml) and water (10 ml) and dried in an oil-pump vacuum (yield: 54%).

EXAMPLE 4 Preparation of the quaterphenyl (1)

3,5,2′,3′,2″-Pentafluoro-4′″-methyl-4-((S)-3-methylpentyl)-[1,4′;1′,1″;4″,1′″]-quaterphenyl (11)

A solution of (0.1 mmol) of 10, (0.12 mmol) of 4, 14 mg (0.13 mmol) of neopentyl glycol, 95 mg (0.3 mmol) of Ba(OH)₂: 8H₂O, 80 μl (6.08 mmol, mol %) of a 76 mM acetone solution of Pd(OAc)₂ in 2 ml of 95% i-PrOH is stirred at 80° C. for 12 hours. The solvent is subsequently removed under reduced pressure. 2 ml of 2 M HCl are added to the residue, and the mixture is extracted with dichloromethane (3×2 ml). The combined organic phases are dried over MgSO₄ and filtered through —SiO₂. The solvent is removed under reduced pressure, and the residue is purified by recrystallisation twice from nonane (yield: 60%).

1% by weight of the quaterphenyl (11) is added to a commercially available nematic base mixture MLC-6260 from Merck KGaA, Darmstadt, and the twisting power HTP of the composition is determined by the Grandjean-Cano method at 2000. The composition has an HTP of −1:9.

EXAMPLE 5 Preparation of the quaterphenyl (13)

2′, 3′,2″-Trifluoro-3,5-dimethyl-4-((S)-3-methylpentyl)-4′″-propyl-[1,4′;1′,1″;4″,1′″]-quaterphenyl (13)

A solution of (0 mmol) of 0, (0.12 mmol) of 12, 14 mg (0.13 mmol) of neopentyl glycol, 95 mg (0.3 mmol) of Ba(OH)₂.8H₂O, 80 μl (6.08 mmol, 5 mol %) of a 76 mM acetone solution of Pd(OAc)₂ in 2 ml of 95% i-PrOH is stirred at 80° C. for 12 hours. The solvent is subsequently removed under reduced pressure, 2 ml of 2 M HCl are added to the residue, and the mixture is extracted with dichloromethane (3×2 ml). The combined organic phases are dried over MgSO₄ and filtered through SiO₂. The solvent is removed under reduced pressure, and the residue is purified by recrystallisation ice from nonane (yield: 65%).

1% by weight of the quaterphenyl (13) is added to a commercially available nematic base mixture MLC-6260 from Merk KGaA, Darmstadt, and the twisting power HTP of the composition is determined by the Grandjean-Cano method at 20° C. The composition has an HTP of −1.5.

1% by weight of the quaterphenyl (13) is added to a commercially available nematic base mixture MJ-001667 from Merck KGaA, Darmstadt, and the twisting power HTP of the composition is determined by the Grandjean-Cano method at 20° C. The composition has an HTP of −1.9.

EXAMPLE 6 Preparation of the quaterphenyl (15)

2′,3′,2″-Trifluoro-3,5-dimethyl-4-((S)-1-methylheptyloxy)-4′″-propyl-[1,4′;1′,1″;4″,1′″]-quaterphenyl (5)

A solution of (0.1 mmol) of 10, (0.12 mmol) of 14, 14 mg (0.13 mmol) of neopentyl glycol, 95 mg (0.3 mmol) of Ba(OH)₂.8H₂O, 80 μl (6.08 mmol, 5 mmol %) of a 76 mM acetone solution of Pd(OAc)₂ in 2 ml of 95% i-PrOH is stirred at 80° C. for 12 hours. The solvent is subsequently removed under reduced pressure. 2 ml of 2 M HCl are added to the residue, and the mixture is extracted with dichloromethane (3×2 ml). The combined organic phases are dried over MgSO₄ and filtered through SiO₂. The solvent is removed under reduced pressure, and the residue is purified by recrystallisation twice from nonane (yield: 68%).

1% by weight of the quaterphenyl (15) is added to a commercially available nematic base mixture MLC-6260 from Merck KGaA, Darmstadt, and the twisting power HTP of the composition is determined by the Grandjean-Cano method at 2000. The composition has an HTP of −12.1.

1% by weight of the quaterphenyl (15) is added to a commercially available nematic base mixture MJ-001667 from Merck KGaA, Darmstadt, and the twisting power HTP of the composition is determined by the Grandjean-Cano method at 20° C. The composition has an HTP of −19.5.

The compounds of the following examples are prepared analogously to Examples 1 to 6 and reaction schemes 1 to 4 using the corresponding starting compounds:

EXAMPLES 7 TO 21

TABLE 1

Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.]  7 H H H H H H  8 H F H H H H C 264 SmE 276 SmA 351 N 355 I  9 H H F H H H C 190 Sm? 210 SmC 237 SmA 250 N 335.2 I 10 F F H H H H C 158 SmE 243 SmA 326 I 11 H F F H H H C 197 SmC 218 SmA 300 N 332.5 I 12 H F H F H H C 191 SmC 202 SmA 263 N 304.7 I 13 H F H H F H C 239 SmA 322 I 14 H H F F H H C 174 N 297.5 I 15 F F H F H H C 145 SmA 270 N 274 I 16 F F H H F H C 190 SmA 292 I 17 H F F F H H C 183 N 290.8 I 18 H F F H F H C 177 SmA 282 N 300.1 I 19 F F H F F H C 154 SmA 265 N 269 I 20 F F H H F F C 203 SmA 249 N 250.6 I 21 H F F F F H C 178 SmC 206 SmA 219 N 284.4 I

EXAMPLES 22 TO 46

TABLE 2

Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 22 H H H H H H C 146 Sm? 184 SmC 198 SmA 283 N 336.8 I 23 H F H H H H C 161 SmC 165 SmA 293 N 313.7 I 24 H H F H H H C 128 SmC 162 SmA 186 N 297.6 I 25 H H H F H H C 127 N 297.8 I 26 H H H H F H C 152 SmA 227 N 307.0 I 27 F F H H H H C 105 Sm? 152 SmA 284 N 287.2 I 28 H F F H H H C 130 SmC (119) SmA 232 N 295.5 I 29 H H H F F H 30 H H H H F F C 152 SmA 268 N 274 I 31 H F H H F H C 139 SmA 266 N 283.9 I 32 H F H F H H C 106 SmC 106 SmA 198 N 272.1 I 33 H H F H F H C 97 SmC 144 SmA 153 N 264.5 I 34 H H F F H H C 120 N 257.7 I 35 F F H F H H C 95 SmA 226 N 245.0 I 36 F F H H F H C 118 SmA 243 N 255.7 I 37 H F F F H H C 129 N 251.0 I 38 H F F H F H C 112 SmC (110) SmA 211 N 260.1 I 39 H F H H F F C 129 SmA 242 N 251.0 I 40 H H F H F F C 122 SmA 197 N 231.5 I 41 H F H F F H 42 H H F F F H 43 F F H H F F C 158 SmA 206 N 223.7 I 44 F F H F F H 45 H F F H F F C 124 SmA 208 N 228.4 I 46 H F F F F H

EXAMPLES 47 TO 71

TABLE 3

Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 47 H H H H H H C 185 Sm? 188 N 330.8 I 48 H F H H H H C 144 SmC (141) SmA 251 N 297.9 I 49 H H F H H H C 118 N 295.1 I 50 H H H F H H C 112 N 299.7 I 51 H H H H F H C 148 SmA 246 N 299.4 I 52 F F H H H H C 150 SmA 260 N 267.9 I 53 H F F H H H C 133 SmA 152 N 287.6 I 54 H H H F F H C 124 SmA 147 N 289.1 I 55 H H H H F F C 136 SmA 260 N 264.0 I 56 H F H H F H C 125 SmA 249 N 271.8 I 57 H F H F H H C 121 N 264.5 I 58 H H F H F H C 128 N 262.6 I 59 H H F F H H C 131 N 267.1 I 60 F F H F H H C 123 SmA 182 N 225.9 I 61 F F H H F H C 152 SmA 240 N 242.0 I 62 H F F F H H C 146 N 256.1 I 63 H F F H F H C 136 SmA 187 N 256.6 I 64 H F H H F F C 151 SmA 243 N 243.0 I 65 H H F H F F C 141 SmA 181 N 226.3 I 66 H F H F F H C 129 SmC 174 SmA 186 N 257.7 I 67 H H F F F H C 146 N 254.8 I 68 F F H H F F C 191 SmA 219 I 69 F F H F F H C 133 SmA 206 N 225.1 I 70 H F F H F F C 145 SmA 208 N 224.5 I 71 H F F F F H C 159 N 245.4 I

EXAMPLES 72 TO 86

TABLE 4

Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions 72 H H H H H H C 131 SmC (113) SmA 186 N 293.6 I 73 H F H H H H C 96 SmA 228 N 270.3 I 74 H H F H H H C 129 N 256.5 I 75 F F H H H H C 117 SmA 226 N 244.4 I 76 H F F H H H C 126 N 254.4 I 77 H F H F H H C 134 N 234.6 I 78 H F H H F H C 120 SmA 217 N 250.0 I 79 H H F F H H C 156 N 222.6 I 80 F F H F H H C 145 SmA 167 N 209.7 I 81 F F H H F H C 150 SmA 202 N 224.7 I 82 H F F F H H C 155 N 214.8 I 83 H F F H F H C 141 SmA 160 N 242.0 I 84 F F H F F H C 159 SmA 172 N 203.8 I 85 F F H H F F C 190 N 205.0 I 86 H F F F F H C 162 N 214.8 I

EXAMPLES 87 TO 111

TABLE 5

Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.]  87 H H H H H H C 118 N 296.0 I  88 H F H H H H C 98 SmA 197 N 269.1 I  89 H H F H H H C 128 N 262.1 I  90 H H H F H H C 134 N 265.1 I  91 H H H H F H C 111 SmA 167 N 263.8 I  92 F F H H H H C 109 SmA 222 N 238.6 I  93 H F F H H H C 143 N 249.2 I  94 H H H F F H C 139 N 253.0 I  95 H H H H F F C 129 SmA 205 N 229.7 I  96 H F H H F H C 120 SmA 205 N 244.1 I  97 H F H F H H C 139 N 238.5 I  98 H H F H F H C 136 N 232.1 I  99 H H F F H H C 157 N 234.3 I 100 F F H F H H C 149 SmA 160 N 207.8 I 101 F F H H F H C 128 SmA 204 N 220.1 I 102 H F F F H H C 162 N 222.2 I 103 H F F H F H C 151 N 224.5 I 104 H F H H F F C 134 SmA 204 N 217.1 I 105 H H F H F F C 161 N 200.7 I 106 H F H F F H C 152 SmA 148 N 229.0 I 107 H H F F F H C 164 N 220.4 I 108 F F H H F F C 170 SmA 190 N 199.2 I 109 F F H F F H C 157 SmA 177 N 203.4 I 110 H F F H F F C 169 SmA (158) N 196.9 I 111 H F F F F H C 173 N 212.9 I

EXAMPLES 112 TO 136

TABLE 6

Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 112 H H H H H H C 131 N 318.0 I 113 H F H H H H C 97 SmA 227 N 286.1 I 114 H H F H H H C 131 N 281.2 I 115 H H H F H H C 136 N 274.2 I 116 H H H H F H C 109 SmA 216 N 280.9 I 117 F F H H H H C 94 SmA 251 N 261.8 I 118 H F F H H H C 130 SmA (113) N 271.8 I 119 H H H F F H C 139 N 276.8 I 120 H H H H F F C 146 SmA 234 N 252.5 I 121 H F H H F H C 114 SmA 233 N 262.8 I 122 H F H F H H C 131 N 233.4 I 123 H H F H F H C 130 N 245.2 I 124 H H F F H H C 160 N 241.8 I 125 F F H F H H C 148 SmA 177 N 214.6 1 I 126 F F H H F H C 113 SmA 226 N 235.4 I 127 H F F F H H C 149 N 235.7 I 128 H F F H F H C 144 N 242.3 I 129 H F H H F F C 139 SmA 228 N 234.8 I 130 H H F H F F C 152 SmA 176 N 212.6 I 131 H F H F F H C 151 SmA 176 N 250.7 I 132 H H F F F H C 162 N 240.1 I 133 F F H H F F C 152 SmA 208 N 212.6 I 134 F F H F F H C 151 SmA 204 N 223.2 I 135 H F F H F F C 156 SmA 179 N 210.7 I 136 H F F F F H C 172 N 235.6 I

EXAMPLES 137 TO 151

TABLE 7

Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 137 H H H H H H 138 H F H H H H C 148 SmA 236 N 274.5 I 139 H H H F H H C 132 N 257.8 I 140 H H H H F H C 146 SmA 214 N 267.3 I 141 F F H H H H 142 H H H F F H C 138 N 251.2 I 143 H H H H F F C 186 SmA 217 N 236.3 I 144 H F H H F H 145 H F H F H H C 133 SmA 154 N 238.9 I 146 F F H F H H 147 F F H H F H 148 H F H H F F C 154 SmA 198 N 219.5 I 149 H F H F F H C 141 SmA 173 N 229.5 I 150 F F H H F F 151 F F H F F H

EXAMPLES 152 TO 176

TABLE 8

Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 152 H H H H H H C 150 Sm? (137) N 267.7 I 153 H F H H H H C 153 N 240.5 I 154 H H F H H H C 172 N 240.5 I 155 H H H F H H C 176 N 243.2 I 156 H H H H F H C 157 N 214.9 I 157 F F H H H H C 161 SmA 166 N 207.1 I 158 H F F H H H C 178 N 232.5 I 159 H H H F F H C 173 N 203.1 I 160 H H H H F F C 160 N 203.5 I 161 H F H H F H C 151 N 238.6 I 162 H F H F H H C 174 N 211.1 I 163 H H F H F H C 172 N 210.1 I 164 H H F F H H C 196 N 211.0 I 165 F F H F H H C 185 N (181.3) I 166 F F H H F H C 166 SmA 176 N 193.3 I 167 H F F F H H C 193 N 206.0 I 168 H F F H F H C 176 N 198.8 I 169 H F H H F F C 163 SmA 174 N 193.3 I 170 H H F H F F C 182 N (178.5) I 171 H F H F F H C 183 N 208.1 I 172 H H F F F H C 193 N 206.1 I 173 F F H H F F C 183 SmA (181) N (182.5) I 174 F F H F F H C 188 N (183.0) I 175 H F F H F F C 183 N (173.1) I 176 H F F F F H

EXAMPLES 177 TO 201

TABLE 9

Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 177 H H H H H H C 144 N 281.2 I 178 H F H H H H C 143 SmA 160 N 256.2 I 179 H H F H H H C 164 N 247.3 I 180 H H H F H H C 165 N 249.3 I 181 H H H H F H C 142 SmA 174 N 256.2 I 182 F F H H H H C 139 SmA 200 N 226.7 I 183 H F F H H H C 162 N 241.7 I 184 H H H F F H C 169 N 241.2 I 185 H H H H F F C 144 SmA 207 N 226.8 I 186 H F H H F H C 150 SmA 194 N 234.7 I 187 H F H F H H C 161 N 222.2 I 188 H H F H F H C 162 N 222.2 I 189 H H F F H H C 182 N 216.3 I 190 F F H F H H C 173 N 192.8 I 191 F F H H F H C 154 SmA 193 N 209.0 I 192 H F F F H H C 178 N 209.1 I 193 H F F H F H C 169 N 216.8 I 194 H F H H F F C 157 SmA 197 N 212.6 I 195 H H F H F F C 169 N 193.7 I 196 H F H F F H C 172 N 217.3 I 197 H H F F F H C 179 N 206.1 I 198 F F H H F F C 179 SmA 181 N 192.8 I 199 F F H F F H C 175 N 190.5 I 200 H F F H F F C 176 N 190.4 I 201 H F F F F H C 188 N 201.9 I

EXAMPLES 202 TO 216

TABLE 10

Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 202 H H H H H H 203 H F H H H H 204 H H H F H H 205 H H H H F H 206 F F H H H H 207 H H H F F H 208 H H H H F F 209 H F H H F H 210 H F H F H H 211 F F H F H H 212 F F H H F H 213 H F H H F F 214 H F H F F H 215 F F H H F F 216 F F H F F H

EXAMPLES 217 TO 231

TABLE 11

Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 217 H H H H H H C 172 N 249.0 I 218 H F H H H H C 168 N 228.9 I 219 H H H F H H C 185 N 216.2 I 220 H H H H F H C 169 N 224.0 I 221 F F H H H H — 222 H H H F F H C 185 N 210.6 I 223 H H H H F F C 174 SmA (165) N 199.1 I 224 H F H H F H C 172 SmA (166) N 210.8 I 225 H F H F H H C 182 N 195.5 I 226 F F H F H H C 186 I 227 F F H H F H C 182 SmA 194 N 240.6 I 228 H F H H F F C 181 SmA ? N 190.3 I 229 H F H F F H C 186 N 192.0 I 230 F F H H F F C 194 I 231 F F H F F H C 192 I

EXAMPLES 232 TO 247

TABLE 12

Example R¹ R² Phase transitions [° C.] 232 C₃H₇ C₃H₇ 233 C₃H₇ C₄H₉ 234 C₃H₇ C₅H₁₁ 235 C₃H₇ C₆H₁₃ 236 C₄H₉ C₃H₇ C 127 N 263.6 I 237 C₄H₉ C₄H₉ C 124 N 251.7 I 238 C₄H₉ C₅H₁₁ 239 C₄H₉ C₆H₁₃ 240 C₅H₁₁ C₃H₇ 241 C₅H₁₁ C₄H₉ 242 C₅H₁₁ C₅H₁₁ 243 C₅H₁₁ C₆H₁₃ 244 C₆H₁₃ C₃H₇ 245 C₆H₁₃ C₄H₉ 246 C₆H₁₃ C₅H₁₁ 247 C₆H₁₃ C₆H₁₃

EXAMPLES 248 TO 272

TABLE 13

Example R¹ R² Phase transitions [° C.] 248 C₃H₇ C₃H₇ 249 C₃H₇ t-C₄H₉ 250 C₃H₇ C₅H₁₁ C 99 N 250.6 I 251 C₃H₇ C₆H₁₃ 252 C₃H₇ C₁₀H₂₁ C 93 N 207.9 I 253 t-C₄H₉ C₃H₇ 254 t-C₄H₉ t-C₄H₉ 255 t-C₄H₉ C₅H₁₁ C 133 N140.8 I 256 t-C₄H₉ C₆H₁₃ 257 t-C₄H₉ C₁₀H₂₁ C 115 N 119.3 I 258 C₅H₁₁ C₃H₇ C 103 N 252.5 I 259 C₅H₁₁ t-C₄H₉ C 134 N 144.3 I 260 C₅H₁₁ C₅H₁₁ C 106 N 234.4 I 261 C₅H₁₁ C₆H₁₃ 262 C₅H₁₁ C₁₀H₂₁ C 85 Sm?; N 198.7 I 263 C₆H₁₃ C₃H₇ 264 C₆H₁₃ t-C₄H₉ 265 C₆H₁₃ C₅H₁₁ 266 C₆H₁₃ C₆H₁₃ 267 C₆H₁₃ C₁₀H₂₁ 268 C₁₀H₂₁ C₃H₇ C 103 SmC 114 N 205.1 I 269 C₁₀H₂₁ t-C₄H₉ C 101 SmC 123 N 127.5 I 270 C₁₀H₂₁ C₅H₁₁ C 102 SmC 135 N 197.5 I 271 C₁₀H₂₁ C₆H₁₃ 272 C₁₀H₂₁ C₁₀H₂₁ C 104 SmC 158 N 177.3 I

EXAMPLE 273

Phase transitions [° C.]: C 108 SmA 109 N 133.1 I

EXAMPLE 274

Phase transitions [° C.]: C 113 SmA 141 N 204.0 I

EXAMPLE 275

Phase transitions [° C.]: C 127 N

EXAMPLE 276

Phase transitions [° C.]: C 114 SmC 136 I

EXAMPLE 277

Phase transitions [° C.]: C 131 SmA 143 I

EXAMPLE 278

Phase transitions [° C.]: C 138 SmA 244 I

To a liquid-crystalline compound of the following formula:

is added 1% by weight of the compound of Example 278, and the twisting power HTP of the composition is determined by the Grandjean-Cano method at 20° C. The composition has an HTP of 3.4.

EXAMPLE 279

Phase transitions [° C.]: C 111 SmA 264 I

To a liquid-crystalline mixture which comprises the following compounds:

50% by weight

15% by weight

15% by weight

20% by weight is added 1% by weight of the compound of Example 279, and the twisting power HTP of the composition is determined by the Grandjean-Cano method at 20° C. The composition has an HTP of 6.3.

EXAMPLE 280

Phase transitions [° C.]: C 108 SmA 216 I

To a liquid-crystalline compound of the following formula:

is added 1% by weight of the compound of Example 280, and the twisting power HTP of the composition is determined by the Grandjean-Cano method at 20° C. The composition has an HTP of 6.7.

EXAMPLE 281

Phase transitions [° C.]: C 97 N 190.3 I

To a liquid-crystalline compound of the following formula:

is added 1% by weight of the compound of Example 281, and the twisting power HTP of the composition is determined by the Grandjean-Cano method at 20° C. The composition has an HTP of 0.8.

EXAMPLE 282

Phase transitions [° C.]: C 92 N 112 I

To a liquid-crystalline mixture as disclosed in Example 279 is added 1% by weight of the compound of Example 282, and the twisting power HTP of the composition is determined by the Grandjean-Cano method at 20° C. The composition has an HTP of 1.3.

The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

From the foregoing description, one skilled, in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. 

1. A ring compound of formula XIII

wherein one or two CH groups in the aromatic ring systems of formula XIII may each be replaced by N; Y is a group of formulae XIV to XVII

in which one or two CH groups in the aromatic ring systems may each be replaced by N; m and n are each 1; X is a single bond, —CH₂—CH₂—, —CH═CH—, —C≡C— or

L, independently of one another, are identical or different and are each R, F, Cl, Br, I, OH, OR, SH, SR, CN, NO₂, NO, CHO, COOH, COOR, CONH₂, CONHR, CONR₂, CF₃, NH₂, NHR or NR₂, wherein at least one L is R or Cl; R is an alkyl, alkenyl or acyl group having up to 12 carbon atoms or an aryl group having 6 carbon atoms which is optionally substituted by an alkyl group having from 1 to 12 carbon atoms; and a, b, c, d, e and f, independently of one another, are identical or different and are each 0, 1 or 2, and the sum a+b+c+d+e+f is 1 to 8; R¹ and R², independently of one another, are identical or different and are each F, Cl, CN, NCS, a straight-chain or branched, optionally chiral alkyl radical or alkoxy radical having from 1 to 12 carbon atoms or an alkenyl radical or alkynyl radical having from 2 to 8 carbon atoms, in each of which, in addition, one CH₂ group may be replaced by —O—, —CO—, —O—CO—, —COO— or —CH═CH—in such a way that heteroatoms are not linked directly to one another and/or one or more H may be replaced by halogen; and in the case where m is 0 or n is 0, one CH₂ group in R¹ or R² may be replaced by one of the following groups: a) trans-1,4-cyclohexylene, in which, in addition, one or more non-adjacent CH₂ groups may each be replaced by —O—or —S—, b) a radical from the group consisting of 1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl, or c) 1,4-cyclohexenylene, and in which the radicals a), b) and c) may also be substituted by CN and/or halogen.
 2. A ring compound according to claim 1, wherein said compound is of formula XVIII

wherein m and n are each
 1. 3. A ring compound according to claim 2, wherein R¹ and R², independently of one another, are identical or different and are each C₁-C₇-alkyl.
 4. A compound according to claim 1, wherein said compound is of the formula I

wherein R¹, R², L, X, m, n, a, b, c, and d are as defined in claim
 1. 5. A compound according to claim 4, wherein X is a single bond.
 6. A compound according to claim 4, wherein X is


7. A compound according to claim 1, wherein at least one L is R.
 8. A compound according to claim 7, wherein at least one L is alkyl.
 9. A compound according to claim 8, wherein at least one L is methyl.
 10. A compound according to claim 4, wherein m and n are each
 1. 11. A compound according to claim 4, wherein at least one L is R.
 12. A compound according to claim 11, wherein at least one L is alkyl.
 13. A compound according to claim 12, wherein at least one L is methyl.
 14. A compound according to claim 1, wherein at least one of R¹ and R² is a chiral branched alkyl radical or chiral branched alkoxy radical having from 1 to 12 carbon atoms, in each of which, in addition, one CH₂ group may be replaced by —O—, —CO—, —O—CO—, —COO— or —CH═CH— in such a way that heteroatoms are not linked directly to one another and/or one or more H are each optionally replaced by halogen.
 15. A compound according to claim 1, wherein at least one of R¹ and R²is isopropyl, 2-butyl, isobutyl, 2-methylbutyl, isopentyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentyloxy, 3-methylpentyloxy, 2-ethylhexyloxy, 1-methylhexyloxy, or 1-methylheptyloxy.
 16. A compound according to claim 1, wherein R¹ and R² are each, independently, H, F, Cl, CN, NCS, a straight-chain or branched, optionally chiral, alkyl radical or alkoxy radical having from 1 to 12 carbon atoms or an alkenyl radical or alkynyl radical having from 2 to 8 carbon atoms, in each of which, in addition, one CH₂ group may be replaced by —O—, —CO—, —O—CO—, or —COO— in such a way that heteroatoms are not linked directly to one another and/or one or more H may be replaced by F.
 17. A compound according to claim 1, wherein R² is a chiral alkyl radical having from 1 to 12 carbon atoms.
 18. A compound according to claim 1, wherein L in each case, independently of one another, identical or different, is F, Cl, CF₃ or CH₃.
 19. A compound according to claim 1, wherein sum a+b+c+d+e+f is 1 to
 8. 20. A compound according to claim 1, wherein sum a+b+c+d+e+f is 3 to
 8. 21. A compound according to claim 1, wherein sum a+b+c+d+e+f is 4 to
 8. 22. A compound according to claim 2, wherein said compound is of formulae XVIIIa to XVIIIg:

wherein L¹-L⁶ are each, independently of one another, are identical or different and are each R, F, Cl, Br, I, OH, OR, SH, SR, CN, NO₂, NO, CHO, COOH, COOR, CONH₂, CONHR, CONR₂, CF₃, NH₂, NHR or NR₂, wherein at least one of L¹-L⁶ is R or Cl.
 23. A compound according to claim 22, wherein said compound is of formulae XVIIIf or XVIIIg.
 24. A compound according to claim 1, wherein said compound is 2′,3′,2″-Trifluoro-3,5-dimethyl-4-((S)-3-methylpentyl)-4′″-propyl-[1,4′;1′,1″;4″,1′″]-quaterphenyl.
 25. A ring compound of formula XIII

wherein one or two CH groups in the aromatic ring systems of formula XIII may each be replaced by N; Y is a group of formulae XIV to XVII

in which one or two CH groups in the aromatic ring systems may each be replaced by N; m and n are each, independently of one another, are identical or different and are each 0 or 1, and the sum m+n is 1 or 2; X is a single bond, —CH₂—CH₂—, —CH═CH—, —C≡C— or

L, independently of one another, are identical or different and are each R, F, Cl, Br, I, OH, OR, SH, SR, CN, NO₂, NO, CHO, COOH, COOR, CONH₂, CONHR, CONR₂, CF₃, NH₂, NHR or NR₂; R is an alkyl, alkenyl or acyl group having up to 12 carbon atoms or an aryl group having 6 carbon atoms which is optionally substituted by an alkyl group having from 1 to 12 carbon atoms; and a, b, c, d, e and f, independently of one another, are identical or different and are each 0, 1 or 2, and the sum a+b+c+d+e+f is 1 to 8; R¹ and R², independently of one another, are identical or different and are each F, Cl, CN, NCS, a straight-chain or branched, optionally chiral alkyl radical or alkoxy radical having from 1 to 12 carbon atoms or an alkenyl radical or alkynyl radical having from 2 to 8 carbon atoms, in each of which, in addition, one CH₂ group may be replaced by —O—, —CO—, —O—CO—, —COO— or —CH═CH— in such a way that heteroatoms are not linked directly to one another and/or one or more H may be replaced by halogen; and in the case where m is 0 or n is 0, one CH₂ group in R¹ or R² may be replaced by one of the following groups: a) trans-1,4-cyclohexylene, in which, in addition, one or more non-adjacent CH₂ groups may each be replaced by —O— or —S—, b) a radical from the group consisting of 1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl, or c) 1,4-cyclohexenylene, and in which the radicals a), b) and c) may also be substituted by CN and/or halogen, with the proviso that group Y is not 